text formating to specific width

user_7644275 0
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I wrote a script to show down- and up-speed of my notebook with polybar. The problem I run into is to put the output of echo in formation.

ATM my output looks like this (bash script loops in terminal) ...

WLAN0: ⬇️ 14 MiB/s ⬆️ 16 KiB/s
WLAN0: ⬇️ 60 B/s ⬆️ 0 B/s
WLAN0: ⬇️ 120 B/s ⬆️ 120 B/s

But I want it lined up, like this ...

WLAN0: ⬇️ 14 MiB/s  ⬆️ 16 KiB/s
WLAN0: ⬇️ 60 B/s    ⬆️ 0 B/s
WLAN0: ⬇️ 120 B/s   ⬆️ 120 B/s

The essence of my code is the following simplified line ...

echo "yada: ⬇️ $string1 ⬆️ $string2"

The variables include a number and text (up to 10 chars max) each, depending on transfer speed.

So there should be at least 12 static fields between the two emoji. But I have no clue how and I am hoping you can explain to me how to format some kind of variables width, with printf I assume.

printf bash
2 Answers

Align left with printf:

string1="14 MiB/s"; string2="16 KiB/s"
printf "yada: ⬇️ %-12s ⬆️ %-12s\n" "$string1" "$string2"

Output:

yada: ⬇️ 14 MiB/s ⬆️ 16 KiB/s

user_37768580

Here you is how you can align columns:

#!/usr/bin/env bash

dnIcon=$'\342\254\207\357\270\217'
upIcon=$'\342\254\206\357\270\217'

nMiBs=14
sMiBs="$nMiBs MiB/s"

nKiBs=16
sKiBs="$nKiBs KiB/s"

printf 'WLAN0: %s  %-10s  %s  %-10s\n' "$dnIcon" "$sMiBs" "$upIcon" "$sKiBs"

Sample output:

WLAN0: ⬇️  14 MiB/s    ⬆️  16 KiB/s
user_79398710
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